Urban Neighborhood is Perfect Place to Grow Lettuce

As the urban garden phenomenon continues to sweep the country, an increasing number of vacant lots are being transformed into green oases that provide fresh, local produce to people living in communities once deemed “food deserts.”

Green City Growers pioneers large-scale hydroponic technology and replaces vacant land in a troubled Cleveland neighborhood.

This gardening trend took a forward leap in northeast Ohio when Green City Growers opened a gigantic greenhouse last year in a troubled Cleveland neighborhood. Larger than three football fields, the facility -- which replaces a large swath of vacant lots -- is now producing millions of vegetables hydroponically; that is, without soil.

Green City Growers is the third of three businesses run by Evergreen Cooperatives of Cleveland. They are employee-owned, for-profit companies. The site of the greenhouse was chosen to help revitalize the surrounding Central neighborhood and provide jobs for its residents.

Three 70,000 gallon tanks like this one collect snow melt and rain water from the greenhouse roof.

I toured the greenhouse with CEO John McMicken to explore the science behind their operation. Our first stop was a row of massive tanks. The greenhouse has three 70,000-gallon tanks that collect rainwater and melting snow from the building’s many roofs. This water is vital to hydroponic growing: each head of lettuce consumes one gallon of water during its growing cycle. Once the company begins operating at full capacity the greenhouse will harvest 10,000 heads of lettuce daily, requiring 10,000 gallons of water a day! At their current capacity nearly all of the water used to grow produce is derived from the collection of rain and snow.

The water that arrives in the tanks doesn’t go straight to work. It is first filtered, purified, oxygenated, and infused with a precise amount of nutrients. The water then moves on to one of 13 nearly 300-foot-long shallow ponds that are used for growing. That water is recycled once a day in order to keep it clean, nourished, and oxygenated.

Only the seeds are started in soil. Workers test a new planting medium (middle containers), a nutrified mulch that is lighter and easier to use than the standard peat moss. The new medium is made locally.

Instead of sprouting from the dirt, hydroponic plants grow in trays that float in nutrient-rich water. At Green City Growers, the seeds are started in soil at a special seeding station. Once the seedlings have a strong enough root system they’re placed in a growing tray, where they begin their journey from one end of the production pond to the other, growing in size as they progress down the line.

Right now, the greenhouse produces three million heads of lettuce and more than 300,000 pounds of herbs every year, with plans to expand in the future. Staples are butterhead lettuce, red and green leaf lettuce, and basil. Watercress was recently added to the growing roster, while greens such as spinach, kale, and arugula are still being tested for viability.

According to McMicken, one of the notable advantages of hydroponic farming is improved food safety. The plants are raised in a contained environment with no pollutants and no environmental contaminants like dirt or bird droppings. Hydroponic growing is also healthier for the plants, McMicken explained, because it allows for tighter control of the nutrients.

These young butterhead lettuce plants are graduating to a tray with more widely spaced holes to allow for growth.

Another safety benefit is the fact that no pesticides are used. If any insects make their way in during the warmer weather, the growers release a few lady bugs onto the plants and let them go to work. The ladybugs eat the invaders and then fly off through the vents in the ceiling. In the peak summer season the greenhouse will occasionally employ wasps to eat any aphids that might be threatening the lettuce.

Another benefit of hydroponic growing, said McMicken, is consistency. The quality and quantity of product is predictable and grown year-round, unaffected by the whims of weather and climate.

Green City Growers distributes 75 percent of its produce within a “local” 100-mile radius of the greenhouse. Sold in grocery stores, restaurants, and hospital systems, this tasty lettuce can go from harvest to a salad bar at the Cleveland Clinic in one or two days -- about as fresh as you can get.

Other companies are also experimenting with large-scale hydroponics and local distribution. BrightFarms in Philadelphia, for instance, uses hydroponic technology to grow vegetables right on the roofs of supermarkets. And some, including Will Allen’s “Growing Power” organization, have paired hydroponic vegetable production with fish farms in a process known as “aquaponics.”

The plants are raised in a contained environment, with no pollutants, no pesticides, and no environmental contaminants.

Christopher Bond, a horticulturist who supervises the hydroponics room at Case Western Reserve University’s Farm Food Program, says he’s seeing more mainstream hydroponics operations come online these days. However, Bond cautions that hydroponics isn’t a panacea for feeding the world’s population; rather, it is just one important method of production. It works particularly well for greens and herbs, he says, but not root vegetables like carrots, perennials like asparagus, or beans, which require runners.

Although this growing method has its limitations, in urban areas like this where fresh vegetables can be hard to come by but vacant lots are plentiful, hydroponic technology could prove to be a useful tool for cultivating food, business, and community.